Liquid fuel injection pumps for internal combustion engines



F. M. EVANS Dec. 15, 1964 LIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Filed Sept. 1'7, 1962 United S tates Patent @ffrce i 3,161,134 LIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Fraser Mackie Evans, Uxbridge, England, assignor to CAN. Limited, London, England Filed Sept. 17, 1962, Ser. No. 223,952

Claims priority, application Great Britain Sept. 19, 1961 1 Claim. (Cl. 103-2) movement relative to the rotor 4 are a pair of shoes 9 against which the outer ends of the plungers 5 bear, Moreover, the shoes 9 carry a pair of rollers 10 respectively which are adapted to make contact with a surrounding annular cam 11 as the distributor rotates, the cam 11 being secured to the housing 2a. The wall portion of the cup-shaped extension 6a is arranged to bear against the end of the body 2, so that any longitudinal thrust imparted to the driving shaft 6 by the engine is borne by the body 2. Moreover, the reduction in diameter of the end of the rotor 4 permits slight tilting of the driving shaft 6 without impairing the operawith the rotor for rotating the rotor and distributor, and

passages in the body and distributor whereby, as the rotor and distributor are rotated, fuel can be fed to said bore whilst the plunger moves outwardly, and subsequent inward movements of the plunger by the actuating means will cause fuel to be fed in turn to a plurality of ports in the body which are adapted for connection to 'the engine cylinders.

The object of the invention is to provide such a pump in a convenient form.

According to the invention, a pump of the kind specified includes a cup-shaped extension at the end of the driving shaft adjacent the rotor, said extension having a cylindrical wall portion which is located between the rotor and the actuating means, an aperture in the wall portion aligned with the end of the transverse bore containing the plunger, and a radially slidable push piece within said aperture and bearing against the end of the plunger, said push piece being adapted to contact the actuating means as the rotor is rotated.

In the accompanying drawings, FIGURE 1 is a sectional side view illustrating one example of the invention, FIGURE 2 is a sectional plan of part of FIGURE 1 with the governor omitted, and FIGURE 3 is a transverse section through the rotor in FIGURE 2.

Referring to the drawings, there is provided a stationary hollow body 2 within which is rotatably mounted a cylindrical distributor 3. At one end the distributor 3 has formed integrally therewith the rotor 4 of an injection pump, the rotor being of similar diameter to the distributor except at its outer end, where it is of slightly reduced cross-section. Within the rotor is adiametrical bore within which are contained a pair of plungers 5.

Adjacent to and coaxial with the rotor is a driving shaft 6 adapted to be driven by the engine through gearing 7, 8. The outer end of the shaft 6 is supported by a hollow housing 2a secured to the body 2, and the inner end of the shaft 6 is formed with an integral cup-shaped extension 6a of greater diameter than the remainder of the shaft. Within the base of the extension 6a is a slot which is engaged by a tongue 4a on the rotor, so that the shaft 6 serves to rotate the rotor 4 and distributor 3. The cylindrical wall portion of the cup-shaped extension 6a is located around the rotor 4, and has formed therein a pair of apertures formed as extensions of said slot and in register with the opposite ends of the bore in the rotor. Slidably mounted in these apertures for radial tion of the pump, whilst the shoulder 12 between the extension 6a and the remainder of the driving shaft 6 can conveniently be employed to secure in position a contrifugal governor 13 surrounding the driving shaft.

At the opposite end of the distributor 3 is a feed pump 14 of the vaned rotor type, the feed pump rotor being integral with but of greater diameter than the distributor 3 and being slotted to accommodate the vanes. Moreover, passages 15, 16 are formed in the body and distributor respectively whereby the feed pump 14 can feed fuel to the bore in the rotor 4 in known manner to move the plungers 5 outwardly, whereafter inward movements are imparted to the plungers by the cam 11 to cause fuel to be delivered in turn to ports 17 in the body adapted for connection to the engine cylinders respectively. The quantity of fuel delivered is determined by a throttle 18 in the passage 15. The throttle 18 is controlled by the centrifugal governor 13 through linkage and spring means in a manner well known per se but not shown.

In the example described the shoes 9 and rollers 10 together form push pieces for co-operation with actuating means in the form of the annular cam 11. However, in a modification the push pieces may comprise shoes with cam surfaces formed thereon, or secured thereto, the cam surfaces co-operating with actuating means in the form of rollers on a surrounding hollow cylindrical sleeve.

By the construction described, backlash between the driving shaft and shoes is minimised, with consequential reduction in the risk of excessive Wear or irregular injection.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

A liquid fuel injection pump for a multi-cylinder internal combustion engine, and comprising in combination a stationary hollow body provided with a plurality of ports adapted for connection respectively to the engine cylinders, a rotary distributor mounted in said hollow body, a rotor which is rigidly united coaxially with one end of said distributor, and which is provided with a transverse bore, at least one plunger slidably mounted in said transverse bore, actuating means surrounding said rotor for imparting inward movements to said plunger during rotation of said rotor and said distributor, a driving shaft which is adjacent to and coaxial with said rotor, co-operating parts on the rotor and the driving shaft, engageable to impart rotation of the driving shaft to said rotor and said distributor, passages provided in said hollow body and said distributor so that, during rotation of said rotor and said distributor, liquid fuel under pressure can be fed to said transverse bore for moving said plunger outwardly towards, said actuat- Patented Dec. 15., 1964 ing means, and can be subsequently discharged through said ports in turn by inward movements imparted to said plunger by said actuating means, a cup-shaped extension which is integrally formed on the end of said driving shaft adjacent said rotor, and which has a cylindrical wall portion located between said rotor and said actuating means, and provided with at least one radical aperture in alignment with said transverse bore, and a radially movable push piece which is slidably mounted in said radial aperture, and which bears against an adjacent endof said plunger so that the latter causes said radially movable push piece to contact said actuating means during rotation of said' rotor and said' distributor irrespective of any relative angular displacement of the driving shaft and rotor.

References Cited in the file of this patent UNITED STATES PATENTS 2,674,236 Humber Apr. 6, 1954 2,946,292 Chmielecki July 26, 1960 2,989,003 Evans June 20, 1961 3,000,318 Volossevich Sept. 19, 1961 FOREIGN PATENTS 212,429 Australia Jan. 30, 1958 1,219,875 France Dec. 28, 1959 857,970 Great Britain Ian. 4, 1961 

